Need help with resistor values to replace a mix pot

I have an early DC-5, which has a parallel loop and a mix knob. The mix essentially goes from a 10/90 split to a 90/10 split, but never quite seems to fully bypass or go series at either extreme of the pot. Rather than just converting it to serial (which would be fine), I want to get fancy and replace the pot with a 5-way rotary switch set up as follows (left to right):

Pos 1: loop bypass
Pos 2: 25% loop, 75% dry
Pos 3: 50/50 mix
Pos 4: 75% loop, 25% dry
Pos 5: Series loop

Position 1 and 5 seem like they should be simple enough.

For position 3, it seems like a 25k resistor more-or-less mutes one side or the other. So do I just run ~12.5k on each side? Or does the math not work out right that way? And same question for positions 2 and 4... Do I just run ~6.25k and ~18.75k resistors? or Do I need something different?

This really isn't a must-have for me, but figured I'd give it a shot if it's as simple as I think it would be.

I ended up scrapping this switch. It just wasn't a necessary feature and the switch I had didn't fit too well inside the amp.

In case anyone is wondering, fairly linear values correspond fairly well with the pot values. You could use all 6k resistors to achieve what I was after. You just use 3 resistors to bridge the terminals of the rotary switch so you have 0, then 6k, then 12k, then 18k resistance, then no connection. You can also use 4k, 8k, and 8k resistors for a little more of an audio taper (0, then 4k, then 12k, then 20k, then no connection). You use a 2-pole 5-way switch and cascade the other pole so its values are opposite of the first side (for a total load of 24k at any of the 3 middle positions).